Aeterna Dei Sapientia §24

²⁴ To complete this account We would mention in passing two further instances of St. Leo's unfailing solicitude for the defense of the Catholic Church's unity: his intervention in the dispute concerning the date of Easter, and his great efforts to create an atmosphere of mutual respect, trust and cordiality in the Holy See's public relations with Christian princes. To see the Church at peace was the dearest desire of his heart. He frequently prevailed upon these princes to join forces with the bishops and lend them the support of their counsels "for the concord of Catholic unity," (20) so as to win from Almighty God "a priestly palm, besides a kingly crown." (21)